US3653363A - Downcomer flow control - Google Patents

Downcomer flow control Download PDF

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Publication number
US3653363A
US3653363A US96680A US3653363DA US3653363A US 3653363 A US3653363 A US 3653363A US 96680 A US96680 A US 96680A US 3653363D A US3653363D A US 3653363DA US 3653363 A US3653363 A US 3653363A
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United States
Prior art keywords
reservoir
conduits
downcomer
liquid
evaporator region
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US96680A
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English (en)
Inventor
Nicholas D Romanos
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Combustion Engineering Inc
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Combustion Engineering Inc
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Publication date
Application filed by Combustion Engineering Inc filed Critical Combustion Engineering Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/023—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers with heating tubes for nuclear reactors, as long as they are not classified according to a specified heating fluid, in another group
    • F22B1/026—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers with heating tubes for nuclear reactors, as long as they are not classified according to a specified heating fluid, in another group with vertical tubes between two horizontal tube sheets

Definitions

  • Shell and tube vapor generators typically comprise a bundle of heat exchange tubes adapted to conduct a heating medium enclosed within a pressure shell.
  • a cylindrical baffle plate normally surrounds the tube bundle in spaced relation from the wall of the shell to define an interior, axially extending evaporator region and an annular downcomer flow passage.
  • a feedwater inlet nozzle communicates with the downcomer annulus to admit vaporizable liquid to the unit and an opening is provided at the bottom of the cylindrical bafile plate to effect fluid communication between the downcomer annulus and the evaporator region.
  • means are provided for automatically adjusting the amount of vaporizable liquid supplied to the evaporator region of a shell and tube vapor generator from the downcomer annulus thereof in response to changes in load conditions within the unit.
  • reliance is placed on the fact that, in apparatus of the type involved, changes in operating conditions are manifest by changes in the level of vaporizable liquid contained within the downcomer annulus.
  • the invention contemplates providing a plurality of upstanding conduits within the downcomer annulus, which are adapted to conduct vaporizable liquid from the annulus to the evaporator region of the shell.
  • the conduits are open at both ends with the lower ends being disposed in fluid communication with the evaporator region.
  • the upper end of the conduits are located at different elevations in the downcomer annulus, the arrangement being such as to provide at each level assumed by the liquid within the annulus an amount of conduit area necessary to conduct an amount of vaporizable liquid to the evaporator region that corresponds to that required to maintain stable fluid circulation at the respective conditions of load.
  • FIG. 1 is an elevational section of a vapor generator constructed according to the invention
  • FIG. 2 is plan section taken along line 22 of FIG. 1;
  • FIG. 3 is a development of a portion of the vapor generator of FIG. 1;
  • FIG. 1 illustrates a shell and tube type vapor generator 10 comprising a vertically elongated cylindrical pressure shell 12 that is closed at its opposite ends by upper and lower domed closure members, 14 and 16 respectively.
  • a pair of axially spaced, transversely extending tube sheets, 18 and 20 respectively are integrally attached to the interior shell wall and divide the shell into axially spaced chambers indicated as heating fluid inlet chamber 22, heating fluid outlet chamber 24, and evaporator chamber 26.
  • a plurality of straight, fluid conducting heat exchange tubes 28 extend through the evaporator chamber 26 having their ends connected between the two tube sheets and communicating with the respective heating fluid inlet and outlet chambers 22 and 24.
  • Nozzles 30 and 32 communicate with the respective inlet and outlet chambers for circulating heating fluid from a source (not shown) through the vapor generator 10.
  • the heat exchange tubes 28 are arranged, as shown, in an axially extending tube bundle whose outer periphery is concentrically spaced from the interior surface of the shell 12.
  • An axially elongated, cylindrical baffle 34 surrounds the tube bundle in spaced relation from the shell wall thereby to form an annular space between the wall and the baffle defining downcomer reservoir 36.
  • a feedwater inlet nozzle 38 penetrates the wall of shell 12 and connects with a ring manifold 40 disposed above the upper end of the baffle 34 for supplying feed liquid to the downcomer reservoir 36. Feed liquid is distributed about the circumference of the reservoir by discharging through circumferentially spaced openings 42 depending from the lower side of the manifold 40.
  • the downcomer reservoir 36 is caused to communicate with the chamber 26 as hereinafter more fully described supplying the latter with vaporizable liquid that flows in heat exchange relation with the heating fluid flowing through tubes 28.
  • a lower liquid space 44 and an upper vapor space 48 occupied by the flowing fluid in its various states.
  • the combined hydrostatic and dynamic forces imposed by the flowing fluid establish a specific liquid level 46 in the reservoir 36 for a particular set of operating conditions. As conditions change the position of level will vary between lines 46a and 461;.
  • the vapor space 48 is provided with a number of axially spaced, horizontally extending baffle plates 50 defining a vapor flow path in which the vapor is conducted in cross-flow relation to the tubes in order to enhance heat transfer between the heating medium and the flowing vapor.
  • vapor will extract heat from the heating medium to be dried and to be imparted with a predetermined degree of superheat.
  • a vapor outlet nozzle 56 penetrates the wall of shell 12 to communicate with the flow passage 54 thereby to conduct superheated vapor from the vapor generator to a point of use.
  • means are provided in the herein described vapor generator 10 for automatically regulating the flow of vaporizable liquid from the downcomer reservoir 36 into the evaporator chamber 26 in response to load changes on the unit.
  • This means comprises a plurality of vertically elongated conduits 58 that are disposed in circumferentially spaced relation about the downcomer reservoir 36.
  • the conduits 58 may be attached to the baffle 34 by welding or otherwise suitably secured within the space.
  • the conduits 58 are open ended tubulous members with the lower ends 60 thereof being disposed in substantially coplanar relation and spaced above the upper surface of the lower tube sheet to place the conduits in fluid communication with the body of liquid 44 in the evaporator chamber 26.
  • the arrangement of the conduits is such that vaporizable liquid from the downcomer reservoir 36 will be discharged into the evaporator region at a rate of flow that corresponds to that required to establish stable fluid circulation within the unit at all load conditions.
  • the conduits are formed of different lengths with their upper ends, 62a, 62b, 62c, etc. disposed at different elevations within the reservoir. In this way a different number of tubes, and concomitantly a different amount of flow area, is caused to effect communication between the downcomer reservoir and the evaporator region of the chamber 36 as the liquid level within the reservoir changes.
  • the conduits 58 are arranged in groups as shown in FIG. 3 with each group consisting of one conduit of each of the lengths provided. Alternatively, but less desirably, conduits of equal length can be grouped together and the respective groups circumferentially spaced from one another about the reservoir 36.
  • the bottom of the downcomer reservoir 36 is preferably closed by means of a horizontally disposed annular plate 64 that extends between the lower end of the cylindrical baffle 34 and the inner surface of the shell 12.
  • the plate 64 is provided with sealed openings that pass the lower ends 60 of the conduits 58 whereby to prevent liquid flow to the chamber 26 except through the interior of the conduits.
  • vapor generators providing for liquid bypass the upper ends 62 of conduits 58 will be disposed at levels somewhat higher than those of the preferred embodiment wherein liquid bypass is not employed.
  • Heating fluid from a source is admitted to the inlet chamber 22, passed through tubes 28 and discharged from the outlet chamber 24.
  • vaporizable liquid is admitted to the unit through feedwater nozzle 38 and ring manifold 40 from whence it is discharged into downcomer reservoir 36 to form a body of liquid therein.
  • the so-formed body of liquid will have a level assuming a position somewhere between the lines 46a and 46b depending upon the operating conditions of the vapor generator 10.
  • From the reservoir 36 liquid is supplied to the chamber 26 through the conduits 58, as hereinafter more fully described, where it flows in indirect heat transfer relation with the heating fluid flowing through the tubes 28.
  • the vapor that is generated within the liquid body passes therefrom to the vapor space 48 where it is directed by bafile plates 50in crossflow relation to the tubes 28 thereby to be dried and further heated to some degree of superheat. Heated vapor then flows through the annular flow passage 54 before exiting the unit through the outlet nozzle 56 and conducted to a point of use.
  • conduits 58 At full load conditions all of the conduits will be caused to conduct liquid so that the maximum rate of liquid supply will then be achieved. While a greater or less number of conduits 58 than those illustrated herein maybe employed without departing from the spirit of the invention, it should be recognized that the sensitivity of liquid regulation will vary directly with the number of conduits of different lengths employed in the unit.
  • the invention described herein provides a simple, inexpensive means for regulating the supply of vaporizable liquid to the evaporator region of shell and tube type vapor generators.
  • fluid circulation instabilities that are characteristic of the operation of vapor generators of this type are alleviated or avoided since the supply of liquid to the evaporator region can be accurately regulated over the full load range of unit operation.
  • downcomer reservoir is an annular space surrounding said evaporator region and said conduits are circumferentially spaced about said downcomer reservoir.
  • Apparatus as described in claim 2 including a plurality of conduits having their inlet ends disposed at each elevation wherein said conduits are arranged in groups and said groups are circumferentially spaced about said downcomer reservoir.
  • each of said groups comprises a plurality of conduits each having its inlet end disposed at a different elevation in said downcomer reser- V".
  • a vapor generator comprising:
  • a cylindrical baffle concentrically spaced from the interior wall of said shell dividing said shell into an evaporator region and a concentrically related downcomer reservoir;
  • conduits immersed in said body of liquid within said downcomer reservoir, said conduits having their discharge ends in fluid communication with said evaporator region and their inlet ends arranged at different elevations in said reservoir whereby the number of tubes efl'ective to conduct liquid from said reservoir to said evaporator region will vary according to the depth of said liquid body.
  • conduits are upstanding tubulous members having their axes parallel to that of said cylindrical baffle.
  • Apparatus as recited in claim 6 including a plurality of conduits having their inlet ends disposed at each elevation, said conduits being arranged in groups and mutually spaced within said downcomer reservoir.
  • each of said groups comprises a plurality of conduits each having their inlet end disposed at a difi'erent elevation.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
US96680A 1970-12-10 1970-12-10 Downcomer flow control Expired - Lifetime US3653363A (en)

Applications Claiming Priority (1)

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US9668070A 1970-12-10 1970-12-10

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US3653363A true US3653363A (en) 1972-04-04

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US96680A Expired - Lifetime US3653363A (en) 1970-12-10 1970-12-10 Downcomer flow control

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US (1) US3653363A (enrdf_load_html_response)
CA (1) CA930633A (enrdf_load_html_response)
DE (1) DE2148221A1 (enrdf_load_html_response)
ES (1) ES397285A1 (enrdf_load_html_response)
FR (1) FR2117991B1 (enrdf_load_html_response)
GB (1) GB1356686A (enrdf_load_html_response)
IT (1) IT941913B (enrdf_load_html_response)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3937184A (en) * 1972-12-19 1976-02-10 Siemens Aktiengesellschaft High-pressure steam generator feed water input arrangement
US4180017A (en) * 1977-08-01 1979-12-25 Borsig Gmbh Pipe assembly-heat exchanger-steam drum unit
FR2487951A1 (fr) * 1980-07-31 1982-02-05 Framatome Sa Distributeur pour l'admission d'un fluide a vaporiser dans un generateur de vapeur
US6435139B1 (en) * 2000-12-14 2002-08-20 Borsig Gmbh Waste heat boiler for cooling hot syngas
US20090272513A1 (en) * 2008-05-02 2009-11-05 Steven Craig Russell Methods and systems for controlling temperature in a vessel

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI60299C (fi) 1980-01-24 1983-06-28 Rintekno Oy Foerfarande foer foeraongning av vaetska och anordning foer geomfoerande av foerfarandet

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147743A (en) * 1962-05-08 1964-09-08 Combustion Eng Vertical recirculating type vapor generator
US3447509A (en) * 1965-01-18 1969-06-03 Babcock & Wilcox Co Once-through vapor generator
US3503440A (en) * 1968-12-23 1970-03-31 Combustion Eng Formed plate tube support

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3385268A (en) * 1965-01-18 1968-05-28 Babcock & Wilcox Co Method of operating a once-through vapor generator
GB1086243A (en) * 1965-01-26 1967-10-04 Atomic Energy Authority Uk Improvements relating to pressurised vapour generators

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147743A (en) * 1962-05-08 1964-09-08 Combustion Eng Vertical recirculating type vapor generator
US3447509A (en) * 1965-01-18 1969-06-03 Babcock & Wilcox Co Once-through vapor generator
US3503440A (en) * 1968-12-23 1970-03-31 Combustion Eng Formed plate tube support

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3937184A (en) * 1972-12-19 1976-02-10 Siemens Aktiengesellschaft High-pressure steam generator feed water input arrangement
US4180017A (en) * 1977-08-01 1979-12-25 Borsig Gmbh Pipe assembly-heat exchanger-steam drum unit
FR2487951A1 (fr) * 1980-07-31 1982-02-05 Framatome Sa Distributeur pour l'admission d'un fluide a vaporiser dans un generateur de vapeur
US6435139B1 (en) * 2000-12-14 2002-08-20 Borsig Gmbh Waste heat boiler for cooling hot syngas
US20090272513A1 (en) * 2008-05-02 2009-11-05 Steven Craig Russell Methods and systems for controlling temperature in a vessel
US8287815B2 (en) * 2008-05-02 2012-10-16 General Electric Company Methods and systems for controlling temperature in a vessel

Also Published As

Publication number Publication date
DE2148221A1 (de) 1972-06-29
IT941913B (it) 1973-03-10
FR2117991B1 (enrdf_load_html_response) 1975-08-29
ES397285A1 (es) 1974-05-01
CA930633A (en) 1973-07-24
FR2117991A1 (enrdf_load_html_response) 1972-07-28
GB1356686A (en) 1974-06-12

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